Eurycoma longifolia is a small, evergreen tree with spirally arranged, pinnate leaves 20–40 cm (8–16 inches) long with 13–41 leaflets. The flowers are dioecious, with male and female flowers on different trees; they are produced in large panicles, each flower with 5–6 very small petals. The fruit is green ripening dark red.

The plant parts have been traditionally used for its antimalarial, aphrodisiac, anti-diabetic, antimicrobial and antipyretic activities.

Amargo is a small tropical tree, growing only 2-6m in height. It is indigenous to Brazil, Peru, Venezuela, Suriname, Colombia, Argentina, and Guyana. It has beautiful red flowers and fruits that turn red as they mature.

Throughout South America, amargo is a tribal remedy for debility, digestion problems, fever, liver problems, parasites, malaria, snakebite, and back spasms, it are used to stimulate the appetite and secretion of digestive juices, as well as to expel worms and intestinal parasites. In herbal medicine in the United States and Europe, amargo is employed as a bitter tonic for stomach, gallbladder, and other digestive problems (by increasing the flow of bile, digestive juices, and saliva); as a laxative, amebicide, and insecticide; and to expel intestinal worms.